This invention relates to a push-button switch and, more particularly, to a push-button switch with a display device, in which a touch panel is arranged on the top side of a push-button switch and a plurality of switching devices are disposed on a single operating button.
In the prior art, a push-button switch of this kind is provided with an LCD (liquid-crystal display) element arranged as a display device on the top side of an operating button. The LCD element is made to display the function of the push-button switch by an IC having a driver circuit and the like, and the switching operation is performed by moving the operating button up and down.
In another example of such a push-button switch, an LCD element is arranged on the under side of a transparent-electrode switch of the type in which transparent electrodes are set on the inner surfaces of a pair of transparent, electrically insulative sheets arranged facing each other across a prescribed gap. The LCD element is made to display the function of the transparent-electrode switch, and the switching operation is performed by pressing the transparent electrodes of the transparent-electrode switch thus made to present a display.
A disadvantage of these conventional push-button switches is that the switch can be operated accidentally as a result of the push-button being contacted inadvertently by the arm or some other object. This can cause the generation of an erroneous signal and result in a changed display while the operator is unaware. One consequence can be a major accident.
Another problem is that since the switch having the touch panel is operated merely by touching the panel with a finger, the operator has no sensation of having actually operated the switch. In other words, the switch does not provide the operator an adequate operating sensation.